EF0 tornado, Columbiana, Alabama, December 22, 2011

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF0

Date

December 22, 2011

Touchdown

1:42 PM CST (19:42 UTC)

Lifted

1:45 PM CST (19:45 UTC)

On the ground

3 minutes

Path length

1.8 miles (2.9 km)

Path width

50 yards (46 m)

Deaths

0

Injuries

0

Property damage

$45,000

County

Shelby County

Touchdown point

33.183, -86.607

Lift-off point

33.203, -86.586

Record number

1112221342-01

3 damage points were recorded along this path by NWS BMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF0. The highest wind the damage implies is 60 mph.

• minor damage to tree limbs

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

In response to a strong upper level shortwave, a surface low developed over the northwestern Gulf of Mexico and rode along a previously stalled front across northwest Central Alabama, Thursday, December 22, 2011. Much of Central Alabama resided in an unseasonably warm airmass, with dewpoints near 70 degrees and CAPE over 1000 J/kg. As the surface low passed over northwest Central Alabama and low level winds backed, helicity increased. Rotating supercells within several thunderstorm complexes produced six tornadoes and isolated wind damage.

National Weather Service meteorologists surveyed damage in Shelby County and assessed damage that was consistent with a tornado. An EF-0 tornado with winds of 70 to 80 mph briefly touched down in Columbiana along County Road 47 and moved northeast for 1.9 miles and lifted along County Road 25. Along its path, 2 homes were damaged due to falling trees, and another home suffered minor shingle damage. Approximately 50 trees were either snapped or uprooted.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

49 minutes of warning. NWS BMX issued a tornado warning for this county at 18:53 UTC, 49 minutes before the tornado touched down, in force until 19:45 UTC.

The county was under a tornado watch, issued at 16:00 UTC and running to 21:04 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 16:27 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Alabaster (EET), 17 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Birmingham radar (KBMX), 16 km away, was scanning. The volume nearest the touchdown began at 19:43 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2011 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

12 more were confirmed in the United States that day.

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.